“…Brazilian data (KOHN et al, 1988;MARTINS et al 2003MARTINS et al , 2005MARTINS et al , 2009MADI;SILVA, 2005;BARROS et al, 2006BARROS et al, , 2007BARROS et al, , 2010PARAGUASSÚ;LUQUE, 2007;VICENTIN, 2009;RODRIGUES, 2010) show that to date, most investigations dealing with parasites of hygiene and sanitary importance in H. unitaeniatus, H. malabaricus or P. nattereri have been conducted on specimens caught in aquatic environments of the Brazilian Amazon region. The only other investigations have been the studies by Martins et al (2005) dealing with H. unitaeniatus and H. malabaricus from the swamplands of the State of Maranhão; Barros et al (2006) with P. nattereri from the metropolitan area of Cuiabá, State of Mato Grosso (MT); Barros et al (2007) with H. malabaricus from the municipality of Santo Antonio do Leverger, MT;and Barros et al (2010) with P. nattereri in the Cuiabá river, municipality of Barão de Melgaço, MT.…”